Drill



July 2 1925 1,547,459

' G. A. STAFFORD ET AL DRILL Filed Dec. 22. 926 2 Sheets-Sheet l 'MMW July 28, 1925. 1,547,459

- G. A. STAFFORD ET AL DRILL Filed Dec. 22. 1925 2 Sheets-Sheet 2 v a glvvvemtg'u' Patented July 28, i925.

1,547,459 PATEN oFFlcagf;

- GEORGE A. sTArroRn AND ALEXANDER s. nonson, or soon LAKE-TEXAS.

' Dem.

Application flled- December and ALEXANDER S. HUDsoN, citizens of the;

United States, residing at Sour Lake, in the county of Hardin and State of Texas, have invented certain new and useful Improvements in a Drill, of which the following is a specification. I

This invention relates to new and useful improvements in adrill.

()ne object of the invention is to provide a drill specially designed for use in drilling through rock and shale in theprocess of drilling wells, but which is also capable of use for general drilling purposes.

Another object of the invention is to provide a drill 6f the" character described which, bythe variation in size, of certain parts, may be used for drilling holes of various diameters.

A further feature of the inventionis to provide a drill of the character described whose worn parts may be readily replaced andthe bit, as a whole thereby renewed.

A still further feature of the invention is to provide'a' drill of the character described which is of very sturdy construction, which may be produced cheaply and which, when dull, or worn, may be renewed.

With the above and other objects in view, this invention has particular relation to cer tain novel'features of construction, operation, and arrangement of parts, an example of which isgiven in this specification and illustrated'in the accompanying drawings, wherein Figure 1 shows a side view partly in section. g

Figure 2 shows a point view thereof." Figure 3 shows a plan view.

Fi' re 4 shows a cross sectional view the line 44 of Figure 1; and,

Figure 5 shows a fra entary side view, partly in section, showing a point of the sh tail type.

Referring now more'particularly to the drawings, wherein like "numerals. of reference designate similar parts in each of the figures, the numeral 1 designates the bit shank whose up er end is reduced and'outcheaply and easily of the bit,

wardly threade to receive the drill collar 2. Beneath the reduced portion, the shank flares downwardly, as" at 2', and is toothed so that if the drill becomes stuck in the bore 22, 1923. Serial No. 682,159.

by bowlders or the like, falling in upon it,

it can cut itself outand thus be withdrawn. 1 Beneath the flared portion there is an integral central downward extension, or mandrel 3, square in cross section, andwhose lower end is round and externally threaded, as at 4, to receive a point, or pilot bit as 5 or 5. Fitted onto the mandrel and interposed between the pilot bit and the enlarged part of the shank, there is a plurality of relatively thick discs 6 forming the body of the drill. This body, as a whole, converges, or tapers downwardly, as shown. Glam ed between the discs, and also between the p1lot bit and the enlarged shank, and the respective adjacent discs are the radiating cutters 7, which are fitted into; suitable seats provided for them, and into which their inner ends fit. t

Each cutter has two or more vertical key ways, as '8, and the wall of the corres onding seat has a similar key way 9, and

keyways 8 to lock the cutters against detachment, all of which is shown in the drawings. Each key is elongated and one end thereof is fitted into a seat, as 10, provided for it in the adjacent part of the drill, as shown in Figures 1 and 5. The two keywa s in the cutters 7, provide'means for the ad ustment of the cutters out or in, so that asthey become worn ofi' they may be ad justed outwardly. The outer ends of these cutters, as well as" their lower sides are beveled, so as to present sharp cutting edges to the material to be cut away. There is a water course 11 extending down through the keys are seated in the keyways 9 and one of the grooves 13, around the drill from 'its'lower to its upper end. The; pilot bit 5 is ofa-- general inverted conical contour and its surface is toothed as shown 1n Flgures 1 and 2. To itslower end there are secured the radiating cutters 14. In the form shown in Figure'5, the pilot bit is of theform of the usual fish tail bit. g

. It is obvious that certain mechanical chan es maybe made in the construction of this grillwithout departin from the principle of the invention an we hereby reserve the right to make such mechanical changes, as will not depart from the scope of the appended claims.

What we claim is: I

1. A drill bit comprising a reduced outwardly threaded shank, an annular downwardly flared shoulder adjacent to said shank having peripheral teeth, a mandrel polygonal in cross section below said shoulder, discs secured on said mandrel, ad'ustable cutters clamped between said isc's, means for securing said cutters against detachment, said cutters being arranged spifor securing said cutters in said discs, and. a bit secured upon the end of said mandrel. 3. A drill bit including an outwardly threaded shank ada ted to receive a drill stem collar, a flare portion beneath said shank provided with peripheral teeth, an ining a threaded lower endaa plurality of discs fitted over said'f-mandrel, said discs.

having a downwardlyconverging contour, cutters clamped between said discs, said cutters being radially adjustable, means for securing said cutters in position between the discs, and a pilot bit having threaded connection with the threaded end of said mandrel.

'wardl flared portion beneath ,Said shank provi' ed with peripheral teeth, a central mandrel beneath said flared portion, a plurality of discs adapted to. be inserted over. .saidmandrel, said discs forming a downwardly converging frusto-conical shaped body, said body having a spiralled peripheral groove, radially adjustable cutters ar- 4. 'A 'drill bit including a shank an outtegral downwardlyextending mandrel hav- I i ranged between the discs, means for securing'said cutters in position and the pilot bit secured on the lower end of the mandrel.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses. j

GEORGE-A. STAFFORD. l ALEXANDER s. HUDSON.

" Witnesses:

S. WILLIAMS, E. E. STRANGE. 

